I think this is a legitimate question to ask, as the modules in the SWIFT::Factory:: namespace on CPAN are incomplete and unuseable (someone please correct me if I'm wrong).

I have developed a proprietary approach, involving YAML and Template Toolkit, that I use for generating test SWIFT MT360 and MT398 messages, which could potentially be used for other message types. I'm not currently in a position to post the source, but this will change in a couple of months, and I'm tempted to release something to CPAN then.